Use a USB device in Virtualbox

1. You can see the USB device on the main interface of Virtualbox, or the allocable USB device in the virtual machine, but the gray device is unavailable.
 
2. solution:
 
1) Add a group: vboxusers (added) and USB FS
 
# Groupadd usbfs
 
2) Add common users $ (admin) $ to these two groups.
 
# Cat/etc/group
 
Vboxusers: x: 802: admin
 
Usbfs: x: 803: admin
 
3) modify the fstab file and add the following content:
 
None/sys/bus/usb/drivers usbfs devgid = 802, devmode = 664 0 0
 
4) restart the computer, and make sure that the two options of the USB controller in the Virtualbox virtual machine settings are valid. When using them, insert the USB device and check the allocable USB device list in the virtual machine.